Improvement in key-hole guards



I `.U1\T-Irr.n f STATES PATENT OFFICE.

ELIJAH M ()AT, 0F WATERTOWN, MASSACHUSETTS.

lMPRCVEM-EiNT IN KEY-HOLE GUARDS.

Specification forming part of Letters Patent No. 154,410, dated August25, 18.7111; application filed June 27, 1874.

To all whom t may concern:

Be it known that I, ELIJAH MoAtr, of Watertown, in the county ofMiddlesex and State of Massachusetts, have invented( a new and ImprovedLock, of which the following is a specification:

In the accompanying drawings, Figure 1 represents a side elevation of myimproved lock; Fig. 2, a vertical transverse section of the same on theline c c, Fig. 1 Fig. 3, a side view of the lock, with guard-platesthrown over the key hole around the key;` Fig. 4, a

' detail view of n the main tumbler for working manner that the actionof the key carries theguardplates over the key -hole not occupied by thestem, previous to the throwing of the bolt, so as.to prevent effectuallythe opening of the lock with any other key, and to exclude theintroductionof implements for assisting the movement of the bolt, and ofan additionally protecting latch-tumbler.

My invention consists of a pivoted springtumbler, connected withdouble-pivoted guardplates, the bolt and latch-tumbler in such a mannerthat the throwing of the bolt-is' rendered impossible without a keyfitting the parts moving the guard-plate, bolt, and additionalguard-tumbler.

In the drawings, A represents the bolt of my improved safety 1ock, whichis guided in the usual manner and thrown by a key, B, with slotted bita, engaging in a recess, a', at the rear part of the same. The bolt A isconnected by pins or lugs d, projecting at both sides, with the pivotedmain tumbler C swinging at one side, and the additional pivotedlatchI-ftumbler D at the opposite side of bolt A. The pins d engage indouble T- shaped slots d" ofthe tumblers C and D, both tumblers beingacted upon by band-springs C and Dl which serve to throw the tumblers inopposite directions and lock over the stop-pins d of the bolt. The maintumbler C is provided above its Vslot d with a slotted recess, e, whichembraces a pin, e', of double guard-plates or wards E, which are pivotedabove the bolt and swing at both sides of the same, immediately underthe outer side plates-of the lockcase. The guard-plates E are securelybraced by lateral bars, and provided with slots fat the points at whichthey pass over the stem of the key B, when the same is placed into thekey-hole. The main tumbler G is also recessed to fit over the stem ofthe key and provided around this,reccss g with a raised and inclinedcam, g, for the purpose of .being acted upon by the spurs or projectionsg2, formed by recessing the bit of the key back of its slotted portion.The turning of the key causes, first, the catching of the spurs over thecam g1, thereby the carrying down of the main tumblerso as to releasethe stop-pin d from its slot, and throw the guard plates E around thekey-stem, closing the key-holes completely thereby. The bit engages nextthe bolt-recess, and raises also the latch-tum bler D from the oppositestop pin d, so that the bolt is free to be thrown completely for closingor opening the lock. The spring action on` the main and latch tumblercarries them instantly, on the completion of the boltmovement, back overthe stoppins, 4 and throws the guard-plates sidewise from the key-holes,producing thereby the rigid and secure position of the bolt and theopening of the key holes for the key. No key which is not constructed tocorrespond exactly with the threefold functions it has to perform-viz.,the throwing of the main tumbler and guard plates, bolt, andlatch-tumbler-can, therefore, succeed in forcing the lock, especially asthe closing of the key-holes bythe guard plates, previous to the motionsof the other parts, prevents the introduction of any implements ordevices for throwing the bolt and releasing the tumblers. The action ofthe key on the parts of the lock, in either direction, is the same, sothat-no intermeddling, feeling, or tampering with the open lock ispossible.

Having thus described my invention, I claim as new and desire to secureby Letters Patent- 1. -The combination of pivoted main tumbler C, havingslots d and e, with main bolt A, and pivotcd double guard-plates E forof key on raised. cam, and releasing' stlpi completion "of `key -actiohy'subs'tntially 's for throwing the bolt, substantially as and. forspecified.

the purpose set forth. l

2. The combination of pivoted main tumbler ELIJAH MOAT'- G,having springC', swinging glmrd-plzit'es,E,A Witnesses: l bolt A, and pivoted latchtumbler D, with ROBERT E. MOAT, spring D' for throwing bolt-afterclosing of ABLEL ABBOTT,

